| Alexey Brodkin | 82be4f0 | 2018-06-15 18:20:59 +0300 | [diff] [blame] | 1 | ================================================================================ |
| 2 | Useful notes on bulding and using of U-Boot on ARC EM Development Kit (AKA EMDK) |
| 3 | ================================================================================ |
| 4 | |
| 5 | BOARD OVERVIEW |
| 6 | |
| 7 | The DesignWare ARC EM Development Kit is FPGA-bases platform for rapid |
| 8 | software development on the ARC EM family of processors. |
| 9 | |
| 10 | Since this board is based on FPGA it's possible to load and use different |
| 11 | versions of ARC EM CPUs. U-Boot is built to be run on the simplest |
| 12 | possible configuration which means the same one binary will work on more |
| 13 | advanced configurations as well. |
| 14 | |
| 15 | The board has the following features useful for U-Boot: |
| 16 | * On-board 2-channel FTDI TTL-to-USB converter |
| 17 | - The first channel is used for serial debug port (which makes it possible |
| 18 | to use a serial connection on pretty much any host machine be it |
| 19 | Windows, Linux or Mac). |
| 20 | On Linux machine typucally FTDI serial port would be /dev/ttyUSB0. |
| 21 | There's no HW flow-control and baud-rate is 115200. |
| 22 | |
| 23 | - The second channel is used for built-in Digilent USB JTAG probe. |
| 24 | That means no extra hardware is required to access ARC core from a |
| 25 | debugger on development host. Both proprietary MetaWare debugger and |
| 26 | open source OpenOCD + GDB client are supported. |
| 27 | |
| 28 | - Also with help of this FTDI chip it is possible to reset entire |
| 29 | board with help of a special `rff-ftdi-reset` utility, see: |
| 30 | https://github.com/foss-for-synopsys-dwc-arc-processors/rff-ftdi-reset |
| 31 | |
| 32 | * Micro SD-card slot |
| 33 | - U-Boot expects to see the very first partition on the card formatted as |
| 34 | FAT file-system and uses it for keeping its environment in `uboot.env` |
| 35 | file. Note uboot.env is not just a text file but it is auto-generated |
| 36 | file created by U-Boot on invocation of `saveenv` command. |
| 37 | It contains a checksum which makes this saved environment invalid in |
| 38 | case of maual modification. |
| 39 | |
| 40 | - There might be more useful files on that first FAT partition like |
| 41 | user applications, data files etc. |
| 42 | |
| 43 | * 256 KiB of "ROM" |
| 44 | - This so-called "ROM" is a part of FPGA image and even though it |
| 45 | might be unlocked for writes its initial content will be restored |
| 46 | on the next power-on. |
| 47 | |
| 48 | |
| 49 | BUILDING U-BOOT |
| 50 | |
| 51 | 1. Configure U-Boot: |
| 52 | ------------------------->8---------------------- |
| 53 | make emdk_defconfig |
| 54 | ------------------------->8---------------------- |
| 55 | |
| 56 | 2. To build Elf file (for example to be used with host debugger via JTAG |
| 57 | connection to the target board): |
| 58 | ------------------------->8---------------------- |
| 59 | make mdbtrick |
| 60 | ------------------------->8---------------------- |
| 61 | |
| 62 | This will produce `u-boot` Elf file. |
| 63 | |
| 64 | 3. To build binary image to be put in "ROM": |
| 65 | ------------------------->8---------------------- |
| 66 | make u-boot.bin |
| 67 | ------------------------->8---------------------- |
| 68 | |
| 69 | |
| 70 | EXECUTING U-BOOT |
| 71 | |
| 72 | 1. The EMDK board is supposed to auto-start U-Boot image stored in ROM on |
| 73 | power-on. For that make sure VCCIO DIP-switches are all in "off" state. |
| 74 | |
| 75 | 2. Though it is possible to load U-Boot as a simple Elf file via JTAG right |
| 76 | in "ROM" and start it from the debugger. One important note here we first |
| 77 | need to enable writes into "ROM" by writing 1 to 0xf0001000. |
| 78 | |
| 79 | 2.1. In case of proprietary MetaWare debugger run: |
| 80 | ------------------------->8---------------------- |
| 81 | mdb -dll=opxdarc.so -OK -preloadexec="eval *(int*)0xf0001000=0" u-boot |
| 82 | ------------------------->8---------------------- |